Camera review site (known for not being slanted in their reviews) to the iPhone 5 for an initial review (longer one comparing to other phones will come later) and dedicated a whole page analyzing the flare issue.
http://www.dpreview.com/articles/6867454450/quick-review-apple-iphone-5-camera [dpreview.com]
Here's their analysis of the flare issue:
"Really, our advice is not to worry. Just do what you should do anyway, and avoid putting bright lights near the edge of the frame when shooting."
Their final conclusion on the 5's camera:
"The iPhone 5 is a fine mobile device, with an excellent camera. In qualititative terms it's not the best camera out there, and nor is it the best camera on a smartphone (the Nokia 808 has that honor, for now) but it offers satisfying image quality, some neat functions like auto panorama and HDR mode, and - crucially - it is supremely easy to use. It isn't much better than the iPhone 4S, as far as its photographic performance is concerned, but it isn't any worse (notwithstanding a somewhat more noticeable propensity towards lens flare). When manufacturers employ pixel-binning to achieve higher ISO settings we don't normally celebrate the fact, but in the case of the iPhone 5, it gives you greater flexibility in poor light (i.e., you might actually get a picture now, where you just wouldn't with the iPhone 4S) and the drop in quality is unnoticeable when the images are used for sharing/web display."

Every optical element shows some sort of dispersion. "Simply" to control when you have the space (like in objectives of real cameras, microscopes or binoculars) but not so easy when your optical element is a simple plate with parallel faces (like a protective glass cover) or a tiny lens. Combine a tiny lens with a tiny CCD and you're out of luck when you hit a difficult to control lighting situation. 8 MP on smartphone "cameras" with tiny optics and tiny CCD-chips is a waste of storage space anyway. You can't get the required optical resolution. Simple physics.

It is not a flaw with the iPhone camera but rather a limitation of the optics of the camera lens that causes chromatic aberration. This is a well-known phenomenon that is is most prevalent in high contrast situations with any camera (unless you spend $$$ for a high-end lens). Taking a picture with the sun high overhead against a dark background is an excellent way to highlight chromatic aberration. The advice from Apple Support is correct in that the user of camera should recompose their picture rather than stir up controversy with blog posts. You'll also note that the pictures on the link are similar but not framed quite identically, which exacerbates to chromatic aberration. And I won't even get into the ridiculous comparison of the fixed focal length iPhone cameras with a professional level Nikon D300.

For a more detailed description and how to avoid it (or fix it - perhaps with iPhoto which is likely installed on your iPhone)http://www.tutorial9.net/tutorials/photography-tutorials/correcting-and-preventing-chromatic-aberration/

Note that camera angle to light source is critical, to get the effect to show up on either phone. In your example comparison, if the photographer tried a bit more he could probably have found the angle to make the purple flare show on the 4S too.

This is a lot of fuss about nothing. But we're used to that with iPhone stories. No other phone gets this level of close examination for flaws. Not enough people care about other phones.

Nah, this is now "rearrange nature." If the sun is in your way. move it. Want to take a picture of your child running in the sprinklers on a sunny day? well that's a moment that cannot be captured.

And the Apple fanboys say if you don't want a camera that adds purple flares (all cameras apparently do this) then get a professional level Nikon D300. Those are your only choices so quit complaining that you didn't get the professional level Nikon D300.

Except, as linked earlier in this thread, the iPhone 4S has the exact same "problem", it just happens in margionally different circumstances. The reason that both the 4S and 5 have it is because they both have saphire scratch resistant lens covers, because this is a phone, not a camera.

I'd like to make a rather pedantic point of clarification here: it is a "chromatic aberration" in the general sense that the system images spurious color, but it is not an aberration caused by dispersion (the variation of refractive index as a function of wavelength), nor is it a Seidel aberration.

If the purple hue comes from incomplete filtering of wavelengths outside the visible range, then it would be easy to test this theory by simply taking four kinds of photos: one that shows the flare with the unmodified camera, one of the same scene with a UV filter placed in front of the lens, a third with an IR filter placed in front of the lens, and finally, one with both UV + IR filters.